Among the isoxazole derivatives represented by the formula (II), the compounds wherein R.sup.3 is cyano are prepared by the known process which is disclosed in JP-A-75471/1985. This process comprises reacting 3,4-diaryl-5-methylisoxazole with a halogenating agent and then with a cyanogenation agent. The compounds of the formula wherein R.sup.3 is alkoxycarbonyl are novel compounds.
An object of the present invention is to provide a novel and preferred process, which is entirely different from the conventional process, for producing isoxazole derivatives represented by formula (II) and useful as intermediates for preparing the compounds (A).